Not Applicable.
In the manufacture of synthetic fibers spun from the melt, the first processing step immediately after the capillaries emerge from the spinning jet, i.e., immediately after formation of the filaments, is the treatment of the fiber surface with spinning finishes containing lubricants and antistatic agents as their principal active substances. It is generally known that synthetic fibers can neither be produced nor used in textile fiber processing without such finishes. A lubricant has to be applied because the original surface of most polymeric fibers gives rise to considerable friction forces so that chafing of the fibers occurs through the constant contacts, for example with guide elements, during the production and processing cycles and can ultimately result in filament or yarn breakages. In addition, polymeric filament materials generally absorb only a little water so that they tend to develop electrostatic charges.
For general commercial acceptability, it is important that fiber finishes for synthetic fibers reduce friction between the yarn and contact surfaces, for example, surfaces of processing machinery or interfaces with other fibers; adhere to the yarn to reduce sling-off during processing; and be scourable to permit substantially complete removal before downstream operations such as dyeing and finishing, with which lubricant residue would substantially interfere. It is particularly important that lubricant compositions consistently function well to perform these tasks under a variety of operating conditions, in order to obviate the necessity of re-evaluating and reformulating each finish/lubricant composition on an ad hoc basis.
Anti-sling additives for fiber lubricants and finishes, especially coning oil type lubricants, are well-known in the art as protective coatings for fibers in a variety of textile operations. Many of these additives, particularly relatively low molecular weight polymers such as polyisobutylene, are in common use to improve adherence of the finish to the fibers, and reduce finish xe2x80x9csling-offxe2x80x9d during yarn winding operations.
While these types of additives have proven to be generally useful in lubricants for low-to-medium speed fiber winding operations, i.e., yarn speeds of up to about 300 meters/minute, in ultra high speed winding operations, conventional low molecular weight polyisobutylene and comparable low-sling polymer additives have not sufficed to reduce lubricant sling-off/spraying to acceptable levels. Moreover, these known additives are not uniformly reliable and tend to perform erractically under varying process parameters, particularly with respect to fiber type, yarn speed, machinery characteristics, processing temperatures, and recirculation conditions. In addition, spraying of the finish also results in a reduction in safety, for example, slippery floors in the immediate vicinity of the machines and also breathing difficulties and skin irritation produced by sprayed droplets which are dispersed in the form of a fine mist.
While the use of polyethylene oxides having weight average molecular weights of more than 106 have been found to be useful as anti-sling additives in spin finishes, they are typically incorporated into fiber finishes in the form of an aqueous suspension, i.e., a suspension of polymer powder in water is mixed with a fiber finish. Although the incorporation of an anti-sling additive in the form of an aqueous suspension is generally acceptable, it does pose certain problems with respect to packaging and formulation. The packaging required when distributing an aqueous suspension is significantly larger and more involved due to the presence of water in a packaging container. Moreover, as to the formulation of an end-use finish composition, the formulator must take the water into account when mixing the aqueous anti-sling additive suspension with the components comprising the finish composition.
Therefore, it is an object of the present invention to devise a way in which the polymer acting as an anti-sling additive can be incorporated into a fiber finish composition, in powder form, thereby eliminating the need of using it as an aqueous suspension.
The present invention is directed to a process for making a fiber finish composition having anti-sling properties involving:
(a) providing a lubricant component;
(b) providing a water component;
(c) providing a powder-form polyethylene oxide having a weight average molecular weight of more than 106; and
(d) mixing (a)-(c) in a static in-line mixing apparatus.